Research and Reports in Gynecology and Obstetrics

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Abstract

Case: 46y G2P0020 with a symptomatic fibroid uterus who desired uterine artery embolization for treatment. On angiogram, she had bilateral atretic uterine arteries with large, tortuous ovarian arteries supplying the uterus and fibroids. Embolization was aborted due to inability to achieve access to the ovarian arteries distal to the ovaries. Ultimately, the patient underwent an uncomplicated laparoscopic supracervical hysterectomy with resolution of symptoms.

Conclusion: Congenital bilateral uterine artery atresia is a rare occurrence. In their absence it is possible for the entire uterine blood supply to be derived from the ovarian vessels. This can present challenges for management via embolization.

Keywords

Introduction

Fibroid tumors are the most common benign condition of the
female reproductive tract. Approximately 80% of black women
and 70% of white women in the United States develop uterine
fibroids [1]. Uterine artery embolization is an increasingly
more common alternative to hysterectomy and myomectomy
for fibroid-associated comorbidities. The success of uterine
artery embolization is contingent on complete blockage of the
vessels supplying the fibroid. For this reason, it is important to
consider the wide array of pelvic vascular anomalies that can
pose challenges in successfully completing these procedures. In
this case, we illustrate an anatomic variation that precluded the
patients preferred method of treatment.

Case Presentation

The patient is a 46 year old G2P0020 with a 14 week sized
leiomyomatous uterus with pelvic pressure and heavy
menstrual bleeding. She had two prior terminations of
pregnancy and had no desire for future pregnancy. After
being counseled regarding options for symptomatic control
of her leiomyomatous uterus, the patient opted for a uterine
artery embolization.

A uterine artery embolization was begun in the usual fashion.
Angiograms during the procedure showed bilateral atretic
uterine arteries with the presumed right-sided uterine artery
supplying only cervical and vaginal branches. Large, tortuous
ovarian arteries provided all of the blood supply to the uterus
and ovaries as shown in Figure 1. Sub selection of arterial
access distal to the ovaries could not be obtained and therefore
the embolization was not performed (Figure 1).

The patient was counseled after the procedure and opted for a
laparoscopic supracervical hysterectomy. At the time of surgery, large, tortuous ovarian vessels were appreciated. Dissection
was notable for absent uterine arteries as shown in Figure 2.
The hysterectomy proceeded without complication and the
postoperative course was unremarkable (Figure 2).

Discussion and Conclusion

In the vast majority of cases, the uterine arteries are the primary
blood supply the uterus and associated fibroids. This case
illustrates an anatomic variation where the bilateral uterine
arteries are absent. Congenital absence of the bilateral uterine
arteries is rare and encountered in less than 1% of cases [2]. This
is a known variant that has been commented on in the radiologic
literature but has not been described in the gynecologic setting.
This patient had a normal menstrual history prior to development
of heavy menstrual bleeding associated with her fibroids, despite
atypical vascular supply.

It is unclear what effect congenital absence of the uterine arteries
would have on a pregnancy. In the reported case above, this
patient had two pregnancies that were electively terminated in
the first trimester. On review of the literature, no other reported
cases are noted and as such we cannot draw any conclusions
regarding potential pregnancy outcomes. It has been speculated
that single uterine artery in the case of unicornuate uteri is
associated with poor fetal growth secondary to sub-optimal
vascular supply; however it is difficult to draw comparisons
given the concomitant abnormal uterine body in those cases [3].

Aside from the absent uterine arteries, it is not uncommon for
fibroids to derive their blood supply from alternate sources.
Often, this is unappreciated until the patient undergoes
angiography prior to embolization or until the time of surgery.
Angiography during uterine artery embolization for fibroids or
adenomyosis demonstrates collateral vessels in 5-12% of cases.
The most common source of collaterals is the ovarian artery (3-
8%) followed by the inferior mesenteric artery (1.3%) [4,5]. A review of the literature includes cases with fibroid blood supply
arising from a variety of other sources include the round ligament
artery, internal pudendal artery, transverse colonic, and other
anomalous vessels [2,4-7]. Typically, these collateral sources
provide blood supply in addition to that derived from the uterine
artery and are a known risk factor for failure of uterine artery
embolization [2,7]. There are also cases where fibroids derive
their supply exclusively from the collateral vessel. The majority
of uterine fibroids are supplied by both uterine arteries but about
0.39% derives their blood supply from a single ovarian artery
[7]. Embolization of the collaterals is sometimes possible but
risks non-target embolization of other organs such as the ovaries
and the colon.

Aberrant vascular supply to the uterus can affect the treatment
options available to the patient. In this case, it was not
possible to sub-select the ovarian artery distal to the ovaries
and avoid non-target embolization of the ovaries. Because
arterial collaterals and aberrant vasculature may warrant a
more extensive embolization with increased procedure time or
radiation exposure some experts have proposed a pre-procedural
MRI angiography to aid in detection of vascular anomalies and
to allow for appropriate procedure planning [8]. This may be
of additional use in pre-operative planning for more complete
patient counseling and would be of use to the surgeon for
anticipation of surgical challenges that may be encountered
intraoperatively.

It is important for the pelvic surgeon to be aware of the anatomic
variations in blood supply to the uterus and associated fibroids
as this may affect the available management options for a patient
or present challenges during surgical intervention.